ES Projects

Groundwater Protection Projects

The A-Mountain Landfill is located between the Santa Cruz River and Mission Road at the eastern base of A-Mountain. This landfill was used for the disposal of municipal solid waste from 1953-1962. Today the City monitors five shallow landfill gas probes quarterly. The landfill is owned and maintained by the City of Tucson.

The Broadway-Pantano Water Quality Assurance Revolving Fund (WQARF) Site is a State Superfund Site which includes the Broadway North and South Landfills. The property is privately owned, however the City of Tucson disposed of municipal solid waste in the Broadway North Landfill in the past. Groundwater contaminated by tetrachloroethene (PCE), above regulatory standards, has been detected. The City was involved a work share agreement with the Arizona Department of Environmental Quality (ADEQ) to monitor groundwater quality from December 2008 - February 2015. The Western Containment System (WCS), which removed and treated PCE contaminated groundwater, operated from March 2003 - October 2012. It was shutdown due to low PCE concentrations in the groundwater extraction wells.

The Congress and Nearmont Landfills are located just south of Congress St on the western bank of the Santa Cruz River. These landfills were used for the disposal of construction debris and municipal solid waste. The two landfills were slated to be developed as a cultural park as part of the Rio Nuevo project. Using funding from the Rio Nuevo project, the City constructed and operated an aerobic bioreactor at the two landfills to stabilize the land surface so that development could proceed. The bioreactor operated from 2001 to 2008 and was dismantled in April 2009 due to lack of continued funding. Today the City monitors boundary landfill gas probes. The landfill is owned and maintained by the City of Tucson.

The Cottonwood Landfill is generally located 0.5 mile north of Ajo way and 0.5 mile west of Interstate 19. This landfill was used for the disposal of municipal solid waste. Quarterly the City monitors sixteen shallow landfill gas probes at the property boundary and annually inspects the landfill.

The Harrison Road Landfill accepted municipal solid waste from 1972 until it closed in 1997. Data indicates soil vapor contaminated with volatile organic compounds (VOCs), specifically tetrachloroethene (PCE), migrated from the waste to the groundwater table and caused groundwater contamination of PCE at levels above regulatory standards. The City operated a deep soil vapor extraction (SVE) system to remove the source of the groundwater contamination, and a groundwater pump and treat system to control and clean up the PCE contaminated groundwater. In addition, a landfill gas flare system was constructed to control the migration of methane and VOCs from the waste. The site is regulated under the Arizona Department Environmental Quality (ADEQ) Solid Waste Unit. The groundwater pump and treat system was shut-down in December 2015 as VOC concentrations have been below regulatory standards since 2013.

The Irvington Landfill is located on the south side of Irvington Rd a quarter of a mile west of Houghton Rd. This landfill was used for the disposal of municipal solid waste. Today the City monitors fourteen shallow landfill gas probes, one nested deep soil vapor well, and four groundwater monitoring wells around the landfill as part of the Arizona Department of Environmental Quality’s (ADEQ) Aquifer Protection Permit (APP). The landfill is owned and maintained by the City of Tucson.

Los Reales Landfill is an active municipal solid waste landfill located near I-10 and Craycroft Rd. The site is regulated by the Arizona Department of Environmental Quality’s (ADEQ) under the Solid Waste Unit, the Water Quality Assurance Revolving Fund (WQARF) program and the Voluntary Remediation Program (VRP). Groundwater contamination of tetrachloroethene (PCE) and trichloroethene (TCE) above regulatory standards has been detected along with other volatile organic compounds (VOCs) at concentrations below regulatory standards from the older, unlined portion of the landfill. The City is operating a groundwater pump and treat system to contain and cleanup the contaminated groundwater. Treated water is used for dust control and is also re-injected into the groundwater. The City is required to report the amount of groundwater extracted annually to the Arizona Department of Water Resources (ADWR). The City entered the VRP program for the remediation and closure of the Southwest Disposal Area (SWDA), an area of the landfill which accepted industrial waste from 1977 to 1980. The City briefly operated a deep soil vapor extraction system at the SWDA to remove VOCs to prevent vapors from contaminating groundwater. Methane extracted from the landfill gas system is sent to Tucson Electric Power Company and used to provide electricity to the community.

The Mission landfill is located near Mission Road and Starr Pass Blvd intersection. This landfill was used for the disposal of Class II trash which includes construction/demolition debris and green waste. The landfill is owned and maintained by the City of Tucson.

The following landfills: 29th Street, Broadway North, Cactus, Columbus, Dragoon, State Pit, and Walnut have had City involvement in the past but today are not owned by the City. Since these properties are currently owned by private interests, the City is not responsible for maintenance or landfill gas monitoring of them at the sites.

The Prudence landfill is located along the western bank of the Pantano Wash north of 22nd Street. This landfill was used for the disposal of municipal solid waste. Today the City monitors twenty perimeter shallow landfill gas probes, three groundwater monitoring wells, and three deep nested soil vapor wells surrounding the landfill. In addition, the City operates a landfill gas extraction system to prevent the migration of methane to neighboring properties. The landfill is owned and maintained by the City of Tucson.

Rio Nuevo North Landfill, formerly known as Linda Landfill, is beneath the asphalt parking lot of the Commerce Loop building facilities, including the City of Tucson Community Services, United Way and Pima Community College. This landfill was used for the disposal of municipal solid waste, landscape waste, and construction debris. Today the City monitors 25 shallow landfill gas probes, and operates a landfill gas extraction system as needed to control migration of methane from the property. The landfill is owned and maintained by the City of Tucson.

The Ryan Airfield Landfill is located in southeastern Avra Valley at the southeast end of the airfield’s runway system. The landfill received residential and commercial refuse from the airfield and homes, farms and businesses located in the surrounding Avra Valley area. The property is owned by the City of Tucson and is leased to the Tucson Airport Authority. Today the City inspects the landfill annually. There are no shallow landfill gas probes at the site because there are no nearby buildings.

The Ryland landfill is generally located 0.5 mile north of Ajo way between the Santa Cruz River and Interstate 19. This landfill was used for the disposal of municipal solid waste. The landfill is owned and maintained by the City of Tucson. Today the City inspects the landfill annually to correct erosion and other potential issues.

The Silverbell Landfill is located along the western bank of the Santa Cruz River next to the Silverbell Golf Course. The landfill was used for the disposal of municipal solid waste. Today the landfill is an Arizona Department of Environmental Quality’s (ADEQ) Water Quality Assurance Revolving Fund (WQARF) site due to groundwater levels of tetrachloroethene (PCE) and trichloroethene (TCE) that exceed regulatory standards. Due to a break in a pipeline owned by Kinder Morgan in 2003, benzene and methyl tert-butyl ether (MTBE) exceeding regulatory standards have migrated into the southern portion of the Silverbell plume. Today the City inspects the landfill annually, monitors landfill gas probes at the boundary quarterly, monitors groundwater wells semiannually, monitors deep soil vapor probes triennially. A conceptual design for a groundwater pump and treat system for addressing the chlorinated solvents (PCE and TCE) has been completed.

St. Mary’s Landfill is located at Menlo Park near Grande Ave and St. Mary’s Rd. The landfill was used for the disposal of Class II trash and debris consisting primarily of green waste and construction debris. Today the City monitors 29 landfill gas probes on a quarterly basis, and inspects the landfill annually for erosion and other potential issues.

The Tumamoc Landfill is located near the intersection of Starr Pass Blvd and Greasewood Rd, at the southwestern base of Tumamoc Hill. This landfill was used for the disposal of municipal solid waste. The landfill is owned and maintained by the City of Tucson. Today the City monitors nine shallow landfill gas probes at the property boundary, and fourteen groundwater monitoring wells surrounding the landfill. Tetrachloroethene (PCE) and nitrates have been detected in the groundwater exceeding regulatory standards. The nitrates are likely due to land uses on surrounding properties (i.e. septic tanks).

The Vincent Mullins Landfill is located on the eastern bank of the Pantano Wash just north of Speedway Blvd. This landfill was used for the disposal of municipal solid waste. Soil vapor contaminated with volatile organic compounds (VOCs), specifically tetrachloroethene (PCE), migrated from the waste to the groundwater table and caused groundwater contamination of PCE exceeding regulatory standards. Today the City monitors twenty-three shallow landfill gas probes, three nested deep soil vapor wells, thirteen groundwater monitoring wells and two privately owned irrigation wells around the landfill. In addition, a landfill gas flare system was constructed to control the migration of methane and VOCs from the waste. The site is regulated under the Arizona Department Environmental Quality (ADEQ) Solid Waste Unit in accordance with the site’s Aquifer Protection Permit (APP). The landfill is owned and maintained by the City of Tucson.

location: Northeast of Kolb Rd and Speedway Blvd

type: Groundwater Protection Project

Leaking Underground Storage Tank Projects

A release of petroleum-based fuels from the former fueling facility occurred and ADEQ reopened LUST File #3208.01. An Assessment was conducted and found soil impacts above Arizona Soil Remediation Levels (SRLs) which included dissolved gasoline compounds, and Light Non-aqueous Phase Liquid (LNAPL) floating on the perched groundwater. The LNAPL consists of old gasoline. The City of Tucson currently operates a Soil Vapor Extraction System and groundwater Pump and treat System to remediate petroleum impacted soil and remove free-phase and dissolved phase gasoline from the perched groundwater table.

The Thomas O. Price Service Center is a primary fueling facility for the City of Tucson, and has been in operation since 1972. The facility is located at the southwest corner of Ajo Way and Park Ave. (Thomas O. Price Service Center Site Map). Historically, the facility maintained 23 underground storage tanks (USTs) for gasoline and diesel. During the late 1980s, the UST system was found to have leaked an unknown amount of fuel into the soil below the fueling tanks, dispensers, and delivery piping. The tanks were emptied and removed from service in the early 1990’s. Gasoline had migrated to a clay layer 90 feet below the site (in the upper groundwater zone), and has since migrated to the north of Ajo Way and beneath Fire Station 10. Today the City operates two soil vapor extraction systems (SVE) to remove contamination from the soil, and also pumps the gasoline from the upper groundwater zone above the clay. Currently, the City monitors 67 shallow and lower groundwater monitoring and remediation wells annually to detect the gasoline and dissolved benzene in the upper groundwater zone and MTBE in both the upper and lower groundwater zones. Benzene exceeds the regulatory standard in the perched groundwater zone. All work is completed under the oversight of Arizona Department of Environmental Quality (ADEQ) Leaking Underground Storage Tank (LUST) Program accordance with the Corrective Action Plan Modification, dated February 11, 2002.